Comparative Efficacy of 12 botanicals and two synthetic insecticides against the lesser grain borer, Rhizopertha
(Fab) (Coleoptera: Bostrichidae) on stored sorghum


ABSTRACT: The efficacy of some botanicals were compared with one another and with that of two synthetic powdered insecticides, Pirimiphos – methyl (Actellic) and permethrin (Coopex) in Nigerian Stored Products Research Institute, Entomology Laboratory Kano, between February and April, 2000 for seven weeks on grains of sorghum. The botanicals tested include Arachis hypogaea, Annona senegalensis,
Dichrostachys platycarpa, Eragrostic major, Euphorbia laterifora, Mitracarpum scabrum, Monechma hispida, Ocimum americium, 0. viride, Parkia Filieoidae,
Pennisetum glaucum
and Striga senegalensis. The botanicals were applied at the rate of 2.0g/100g grains while the synthetic powder were applied at the rate of 0.05g/100g grains. The results show that there was significant difference (P> 0.05) in adult mortality between the treatments after seven weeks of storage. While the two synthetic insecticides resulted in 100% adult. mortality, there was no significant difference between them and Ocimum americanum which gave mean mortality of 93. 25%. not significantly different (P 2: 0.05) in mean percentage adult insect mortality
with 75.76%, 71.16% and 70.52% respectively. D. platycarpa followed with adult mortality of 60.96%; P. filicoidae (bark of stem) and P. glaucum recorded 50.70% and 44.60% respectively. The poor performance of the latter is traceable to the smaller quantity of the botanical admixtured. S. senegalensis, M. hispida and E.
gave mean percentage mortalities of 42.53%, 42.48% and 40.01% respectively, while A. hypogaea with mean percentage mortality of 30.46% was no
significantly different from the control with a mortality of 19.86%.

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